Hey Ya! (mal)

Interesting news this weekend. Apparently everything we’ve done in our entire careers is a “MASSIVE lie” (sic) because all of radiative physics, climate history, the instrumental record, modeling and satellite observations turn out to be based on 12 trees in an obscure part of Siberia. Who knew?

Indeed, according to both the National Review and the Daily Telegraph (and who would not trust these sources?), even Al Gore’s use of the stair lift in An Inconvenient Truth was done to highlight cherry-picked tree rings, instead of what everyone thought was the rise in CO2 concentrations in the last 200 years.

Who should we believe? Al Gore with his “facts” and “peer reviewed science” or the practioners of “Blog Science“? Surely, the choice is clear….

More seriously, many of you will have noticed yet more blogarrhea about tree rings this week. The target de jour is a particular compilation of trees (called a chronology in dendro-climatology) that was first put together by two Russians, Hantemirov and Shiyatov, in the late 1990s (and published in 2002). This multi-millennial chronology from Yamal (in northwestern Siberia) was painstakingly collected from hundreds of sub-fossil trees buried in sediment in the river deltas. They used a subset of the 224 trees they found to be long enough and sensitive enough (based on the interannual variability) supplemented by 17 living tree cores to create a “Yamal” climate record.

A preliminary set of this data had also been used by Keith Briffa in 2000 (pdf) (processed using a different algorithm than used by H&S for consistency with two other northern high latitude series), to create another “Yamal” record that was designed to improve the representation of long-term climate variability.

Since long climate records with annual resolution are few and far between, it is unsurprising that they get used in climate reconstructions. Different reconstructions have used different methods and have made different selections of source data depending on what was being attempted. The best studies tend to test the robustness of their conclusions by dropping various subsets of data or by excluding whole classes of data (such as tree-rings) in order to see what difference they make so you won’t generally find that too much rides on any one proxy record (despite what you might read elsewhere).

****

So along comes Steve McIntyre, self-styled slayer of hockey sticks, who declares without any evidence whatsoever that Briffa didn’t just reprocess the data from the Russians, but instead supposedly picked through it to give him the signal he wanted. These allegations have been made without any evidence whatsoever.

McIntyre has based his ‘critique’ on a test conducted by randomly adding in one set of data from another location in Yamal that he found on the internet. People have written theses about how to construct tree ring chronologies in order to avoid end-member effects and preserve as much of the climate signal as possible. Curiously no-one has ever suggested simply grabbing one set of data, deleting the trees you have a political objection to and replacing them with another set that you found lying around on the web.

The statement from Keith Briffa clearly describes the background to these studies and categorically refutes McIntyre’s accusations. Does that mean that the existing Yamal chronology is sacrosanct? Not at all – all of the these proxy records are subject to revision with the addition of new (relevant) data and whether the records change significantly as a function of that isn’t going to be clear until it’s done.

What is clear however, is that there is a very predictable pattern to the reaction to these blog posts that has been discussed manytimes. As we said last time there was such a kerfuffle:

However, there is clearly a latent and deeply felt wish in some sectors for the whole problem of global warming to be reduced to a statistical quirk or a mistake. This led to some truly death-defying leaping to conclusions when this issue hit the blogosphere.

Plus ça change…

The timeline for these mini-blogstorms is always similar. An unverified accusation of malfeasance is made based on nothing, and it is instantly ‘telegraphed’ across the denial-o-sphere while being embellished along the way to apply to anything ‘hockey-stick’ shaped and any and all scientists, even those not even tangentially related. The usual suspects become hysterical with glee that finally the ‘hoax’ has been revealed and congratulations are handed out all round. After a while it is clear that no scientific edifice has collapsed and the search goes on for the ‘real’ problem which is no doubt just waiting to be found. Every so often the story pops up again because some columnist or blogger doesn’t want to, or care to, do their homework. Net effect on lay people? Confusion. Net effect on science? Zip.

Having said that, it does appear that McIntyre did not directly instigate any of the ludicrous extrapolations of his supposed findings highlighted above, though he clearly set the ball rolling. No doubt he has written to the National Review and the Telegraph and Anthony Watts to clarify their mistakes and we’re confident that the corrections will appear any day now…. Oh yes.

But can it be true that all Hockey Sticks are made in Siberia? A RealClimate exclusive investigation follows:

We start with the original MBH hockey stick as replicated by Wahl and Ammann:

One would think that some things go without saying, but apparently people still get a key issue wrong so let us be extremely clear. Science is made up of people challenging assumptions and other peoples’ results with the overall desire of getting closer to the ‘truth’. There is nothing wrong with people putting together new chronologies of tree rings or testing the robustness of previous results to updated data or new methodologies. Or even thinking about what would happen if it was all wrong. What is objectionable is the conflation of technical criticism with unsupported, unjustified and unverified accusations of scientific misconduct. Steve McIntyre keeps insisting that he should be treated like a professional. But how professional is it to continue to slander scientists with vague insinuations and spin made-up tales of perfidy out of the whole cloth instead of submitting his work for peer-review? He continues to take absolutely no responsibility for the ridiculous fantasies and exaggerations that his supporters broadcast, apparently being happy to bask in their acclaim rather than correct any of the misrepresentations he has engendered. If he wants to make a change, he has a clear choice; to continue to play Don Quixote for the peanut gallery or to produce something constructive that is actually worthy of publication.

Peer-review is nothing sinister and not part of some global conspiracy, but instead it is the process by which people are forced to match their rhetoric to their actual results. You can’t generally get away with imprecise suggestions that something might matter for the bigger picture without actually showing that it does. It does matter whether something ‘matters’, otherwise you might as well be correcting spelling mistakes for all the impact it will have.

So go on Steve, surprise us.

Update: Briffa and colleagues have now responded with an extensive (and in our view, rather convincing) rebuttal.

“Do you think, if all data from every study for all time were freely and easily available, that would have stopped McIntyre from useless unfounded FUD? Or even slowed him down?”

Nope. He would just insinuate that the data was fabricated (which he’s done before) and end up with thousands of like-minded individuals cheering him on in unison. McIntyre excels (like some journalists) because there’s a large public demand for global warming denial, and there are those with basic rhetorical skills to meet such a demand. If he and others simply write boring old posts examining some scientific detail and keeping it in the proper context, they put their politically-oriented readers to sleep and bore media outlets that are looking to promote certain claims. It’s when they make more outrageous claims, such as asserting the hoax has been revealed or referring to climate scientists as “jihadists”…

that they get the attention and notice they crave, far beyond what an objective scientist gets by publishing rigorous peer-reviewed research.

The concern I have is whether or not it’s productive for RC to be spending time on these sorts of matters. It tends to validate antagonistic behaviors. Gutter-snipers would like nothing more than for scientists to pay attention to them. On one hand, disinformation shouldn’t go unchecked, but if it takes away from other important activities and posts covering topics such as…

“Do you really believe that? Do you think, if all data from every study for all time were freely and easily available, that would have stopped McIntyre from useless unfounded FUD? Or even slowed him down?”

I think it’s worth a try. More to the point I think it has to be SEEN to be tried. Otherwise you’re giving him an open goal.

Even if the hockey stick of tree growth is not exaggerated, all it tells us is that trees are consuming more energy and CO2 and turning it into wood. While temperature is one thing that affects the robustness of biomass, the list of other things that do the same is long. One of these is CO2 levels. It seems far more plausible that any additional growth is a result of dramatically increasing CO2 levels and not a tiny increase in temperature that might have occurred during the same time. I don’t see any point in using dendrochronology to tell us that CO2 levels are rising; we already know this. Linking this to temperature increases assumes that rising CO2 levels are causing the temperature increase in the first place. I know that many in the climate science field have rallied around this speculative conclusion, but the tree ring analysis does nothing to establish any significant causal relationship between CO2 levels and temperature.

Is RC stating that all of the data Briffa recently uploaded to his website, the dataset from Yamal and the larger dataset by Hantemirov and Shiyatov from which the Yamal data was selected, was publicly available prior to being posted on Briffa’s CRU site?

[Response: We have no knowledge of that. I would ask H&S since they originated the data that Briffa used. – gavin]

Any idea if Briffa selected the subset of 12 cores, or was it selected for him by H&S?

[Response: He stated very clearly that he processed the data from H&S. – gavin]

Is it true that Briffa’s work gives more weight to tree ring cores that match the instrumental records than those that do not?

[Response: Presuming you are discussing the Yamal chronology, no it is not. – gavin]

Gavin:
“Except that….. people looked over it briefly, there was one formatting error found, there were some half-hearted attempts to look at it…. and nothing. McIntyre et al got bored and went off to find another windmill to tilt at. And people still complain that the data and the code aren’t available.”

That is not how I remember it. First of all, no one seemed to be able to get the code to work. I don’t know if anyone ever has. Then there were operations in the code that didn’t make sense. For example, the way that station data was weighed when it was being used to correct other station data made no sense. It looked like weighing for the 500 km cirle was the same as weighing for the 1000 km circle. So depending on the method used, a station at 400 km could have the same weighing as a station at 800 km. I’d have to go back and get the details, and I can if necessary. Then there is the Hansen time hinge, where data is adjusted up and down depending on which side of the hinge it was on. No one ever understood how such a hinge would correspond to anything in the real world.

[Response: And then they got bored and went home. Precisely. (PS. all of the methodological choices are discussed in the relevant (peer-reviewed) papers). – gavin]

Isn’t it just a wee bit ironic that the side crying out for access to the data demonstrates over (and the latest McFraudit effort is a prime example) that when they get data, they haven’t the foggiest notion of what to do with it?

We hear over and over again that McI is an expert in statistics, and yet he sees no problem mixing in demonstrably unrepresentative data in a painstaking analysis and then crowing that the results change. Can I get a collective “Duh!” While the cries of fraud by McI’s minions are reprehensible (lower than snake excrement, in fact), this whole episode is more prone to inspire pity in me at just how gullible and incompetent they are.

Then we wouldn’t have this silliness. Science is supposed to be about replicating the work of others /and/ knocking it down. The childishness shown on both sides of this debate is extremely disheartening. Especially when one considers what is at stake.

The characterizations used above, that McIntyre has based his ‘critique’ on a test conducted by randomly adding in one set of data from another location in Yamal that “he found on the internet.” and later “found lying around on the web.” weakens, rather than strengthens, this critique. It completely glosses over the ten years of requests leading up to the public archiving of this data. Failure to deal forthrightly and straighforwardly with the facts of this delayed release of data makes the sarcasm far more irritating, in my opinion.

[Response: The russ035w data has been ‘lying around’ on the web since 2001 (at least) judging from the file stamps. And there have not been ’10 years’ of requests. That’s just crap. – gavin]

Two parts of this story do not greatly fill me with confidence. Firstly, most of the convincing temperature proxies seem to only go back a few hundred years. The tree ring chronologies are maybe best placed for cross dating things like tree-line advance – but if recent events have taught us anything, the error bars for a tree-ring temperature reconstruction are large. Other long term proxies seem to differ fairly significantly, so all I’d be certain of for the last 2000 years is ‘not much change.
The second and more contentious issue is that of the recent instrumental record. CET for this year simply didn’t seem above average to me, and various different recent detailed measurement series seem to offer the potential for divergence (although this probably is more of a wait and see problem).

“Isn’t it just a wee bit ironic that the side crying out for access to the data demonstrates over (and the latest McFraudit effort is a prime example) that when they get data, they haven’t the foggiest notion of what to do with it?”

Absolutely. Publish all the data, publish all the code. Then watch them hang themselves with it.

gavin:
“(PS. all of the methodological choices are discussed in the relevant (peer-reviewed) papers). – gavin]”

Yes they are, but they don’t explain why a hinged ajustment mechanism is a good mechanism to imitate a natural phenomena, and while it explains the transition from 500 km to 1000 km, it doesn’t give a justification for why a weighing at 400 km and 800 km would be the same when switching cirles. One needs to be able to look at code to spot those kinds of detail. In my mind that kind of weighting is still a flaw in the code.

[edit]

[Response: Then come up with a better way, edit the code to accommodate your thoughts and see what difference it makes. This is what I tell grad students and it’s what I’m telling you – don’t spend time sitting around wondering whether something is important. Test it and see – and then we can discuss. – gavin]

The Arrhenius equation *ASSUMES* that the reaction is not otherwise limited. The growth of biomass is generally not energy limited. Add CO2 to a greenhouse and it becomes more productive. Reduce the water and they become less productive. All of this occurs without any changes in energy or temperature. Of course, baseless assumptions and a failure to examine all the information is not unique to this case and are endemic among ‘peer reviewed’ AGW biased papers.

Just a quick note: A news.google.com search on the keywords “mcintyre” “yamal” (as of a few minutes before this post) brought up just a handful of hits, with this RealClimate article at the top of the list.

And yes, one of the major points of the last 2000 years is “not much change”: probably a little cooler, occasionally a bit cooler than that (little ice age), maybe once or twice as warm as present – but no wild multiple degree celsius swings on the global scale – and _that_ is what we are going to see in the next century if we’re not careful.

Well Gavin, if you think I’m wrong, explain why biomass responds to changes in energy, water and CO2 while holding temperature constant? Photosynthesis consumes these as it’s only raw materials and converts them to glucose. Changes in any one of them will affect glucose production. All else being equal, then the dependence of chemical reactions on temperature will matter. The simple fact is that all else is not equal. A snarky little ‘clueless’ response will not suffice.

[Response: Because we are not even on the same page here. I have no interest whatsoever in photosynthesis kinetics. I, my work, this site, the whole debate is about the role of CO2 as a greenhouse gas. Something Arrhenius knew very well and which still appears to be a mystery to some. – gavin]

I just don’t get why it was so hard to get the original data from Briffa. What’s to fear? If I were a leading scientist in a mostly new field of study, I would want my work to be validated for the recognition.

“These politically driven demands for more code, more data, more residuals, more notes, more background are basically insatiable and when the people that provide the most, end up being those who are attacked most viciously, it doesn’t help the cause people claim to espouse”.

You do not seem to realise that the case for man made global warming will require us to spend billions and billions of dollars to address it. Thus, the papers and data that make the case are much more than just ‘intersting studies’, but are critical. It is a very simple scientific principle that the data should be available for cross-checking and scrutiny. If not, then we cannot have confidence in the case. To claim that this is politically rather than scientifically motivated is at best misleading, and does your own case no favours.

“Do you really believe that? Do you think, if all data from every study for all time were freely and easily available, that would have stopped McIntyre from useless unfounded FUD? Or even slowed him down?

I don’t.”

I believe the release of all data, freely and easily available, would make McIntyre’s arguments less persuasive to the general public.

[Response: First off, there are no limits to statements such as ‘all data’ – you can always ask for more. Second, the general public are busy people, and don’t generally check everything people tell them. I still see claims that GISTEMP’s code is secret, or that no GCM code is public regardless of the facts. The joy of this as a talking point (as you illustrate) is that it has good traction among people who haven’t been paying attention to how it is being used. – gavin]

I don’t think that publishing all data and code would “shut the denialists up”. But that does not mean it still should not be done!

And in general in this field, there is a lot of gray data running around and a lot of incompletely described methodology. Compare for instance to crystallogrophy where Acta Cryst requires you to archive your data to a repository, before REVIEW. It is very easy to mess up a crystal structure and this process has led to much better and faster correction of false structures. As well as a wealth of publically accessible information for researchers doing followup work, phase diagrams, etc.

Another phenomenal post. In fact, it is one of my favorite RealClimate posts in some time, and that is saying something. I’ll certainly link to it from my own blog. Keep up the good work and continued patience in educating the non-climatologists. My own patience is drawing thin.

Now, have you or anyone else you know of actually *done* anything with this code/data? Can you tell us about any errors/deficiencies that have been uncovered? Can you provide examples of patches that have been submitted to the climate-model code maintainers?

How much cross-checking and scrutinizing of this code/data has been performed? Much of this stuff has been freely available on line for *years*. So what have you done with it?

you ask what would happen when you take out the Yamal data from Kaufman et al.’s reconstruction, providing a graph. When you look closely at the graph, it appears that removing Yamal lowers temperatures by ~0.15-0.2Celsius (difficult to tell from the small scale).

Will is a piece of work. I wrote a column for his paper on deniers and their place in the news. Since it’s a columnist contest I know they’ll read it. Ten years of temperature stability is his claim. Revkin was no help either. Fed Will his lines. Pity, that.

I have a perhaps naive question: The hockey sticks represent GLOBAL average temperatures, right? It would seem that tree ring data represents a small fraction of the earth’s surface and therefore have a negligible effect on the global average numbers, especially tree ring data from a small region such as Yamal.

[Response: Actually many of them only represent the Northern Hemisphere, and some only summer-time temperatures over land. It will vary depending on the sources of the data and their limitations. However, proxy records are not as well distributed as weather stations, and so for these multi-centennial reconstructions there is more weight attached to each proxy than it would be for a weather station at the same spot in an instrumental estimate. In more recent reconstructions, the number of proxies is increasing strongly (especially after 1600) and so each individual proxy is becoming less important. – gavin]

“Peer-review is nothing sinister and not part of some global conspiracy, but instead it is the process by which people are forced to match their rhetoric to their actual results.”

“Peer review” is not a substitute for replication.

I’m sorry. I do have some sympathy for your position. At the same time, I just can’t get my head around the idea that since it is peer reviewed, someone who is skeptical (as all good scientists /should/ be) shouldn’t be able to reproduce it.

You may be against properly releasing the code and data because you don’t want to waste your time with skeptics. I can get that. But from the outside it looks a lot more like you are afraid of what they’d find. Again, I’m sorry, but that’s just the way it is.

I work in software. I know nothing about climate. But what I do know is there is a way to make code and data available “turnkey” so that others can use it. If you are confident in your science, then that’s what you should do. It’s more work, yes, but it is less work than all this silly sniping.

dhogaza @721. It wasn’t Briffa’s data. And as was noted above, at least one dataset has been available for years.

The data as used in the H&S 2002 paper seems to be a different subset of the total data gathered than the data used by Briffa (the numbers of cores used at any one time is significantly different – Briffa uses more which I would regard as a good thing). Until Briffa finally detailed what data he used there was no way to replicate what he had done and see if it was robust.

If you ignore all the allegations of insinuation, insinuations of allegation etc, justified or otherwise, from all quarters, and especially all the nonsense pumped out by the like of James Delingpole in the Telegraph, doesn’t Steve McIntyre still have a point? For ten years or so, the ‘hockey blade’ in the much re-used Briffa (or H & S) Yamal chronology has been based entirely on a tiny number of cores from living trees. Additional cores made from the same species in the same area (indeed in one of the three river valleys used in the Briffa Yamal chronology) have always been available to boost the sample used for the 20th century to an acceptable size, but they weren’t used. Why?

Isn’t that a valid question? One with all sorts of valid possible answers, the provision of which might be ‘meaningful’ to the advancement of palaeoclimatology?

Gavin:
“I, my work, this site, the whole debate is about the role of CO2 as a greenhouse gas.”

What conclusion do you make? -CO2 being a greenhouse gas explains why tree ring width only responds to a change in temperature? Or are you saying that you want respond to the question because it is not within you area of expertise?

Marcus: “CET” doesn’t seem above average to you? First, never use a local regional temperature record to diagnose global change. But… http://hadobs.metoffice.com/hadcet/
My point is that what I observe personally doesn’t match particularly well with the local regional temperature record – despite that record being one of the better respected series in existence. This leads me to ponder if temperature is a good proxy for heat/weather/climate. Not a question of if the record is accurate, but what is the global significance of that variable.

Gavin
In response to PaulC #47 you miss the point about availability of data. The complaint is not that there isn’t enough data. It’s that (in the cases McIntyre complains about) there isn’t ANY data. In order to reproduce the published results, all the original data must be archived and made available. It’s not “more” data that is being requested here. It is the actual (raw) data used to obtain the results and conclusions in the peer-reviewed and published papers.

If the raw data has been corrected to adjust for local factors then this correction process too must be described. Descriptions of algorithms are similarly insufficient. The actual algorithms are essential. Otherwise it looks like you are trying to hide something. Real Science can stand up to the scrutiny. Make (all) the data available and then, as in your example of GISTEMP, there can be no argument. McIntyre and other sceptics have no basis for challenge and must move on.

As Helvio says in #45, if you don’t provide the evidence, it’s not scientific. Your reply there similarly missed the point. Science is PRECISELY about replicability.

You put the cart before the horse when you say that it is important to replicate the *conclusions*. I hope this is just a bad choice of phrase but I’m struggling to understand how any scientist could hold this view. You need to be able to replicate the results. The conclusions are what you draw from the results and, as any good scientist will tell you, the results may not always support the hypothesis.

In summary, every instance where the raw data and methodologies used are not published, leads to a significant weakening of the climate “science”. I struggle to understand the apparent reluctance for some (many) climate scientists to make their evidence available.

[Response: Let me try again then. I am not against the maximum transparency we can achieve – as I said above, my code is open source, my results and the model output from which they derive are all available. There are huge amounts of this kind of stuff all over the place and there is certainly plenty for any student of climate science to spend lifetimes on. Thus this idea that we don’t want to make evidence available is simply nonsense. However, not everything that goes on is in the public domain for various reasons. One is the understandable desire for scientists to get the fruit of their labour in terms of publications etc. before other people (who are often better funded and have more graduate students) come in and pick out the best stuff. Those are valid concerns. As are issues with commercially valuable data such as the national met offices retain rights to. Sometimes data is held back purely out of the desire to tidy it up and make it more usable, but for which time doesn’t get found very readily. Some data is lost due to computer breakdowns, technological obsolesence or bad data management practices (those would be bad reasons). However, some results need work to resurrect – intermediate steps that were erased due to data storage constraints for instance – but that somehow become interesting to someone. That might involve serious work to make public, and given various pressures might not get done. But much of this is besides the point. Many people, and you perhaps, seem to think that exact replication of a result is a key part of it’s validity. It isn’t. I can claim to forecast the climate by counting hairs on the back of my hand. I can provide photos of each hair, spreadsheets of the count and exact locations that can be verified by anyone and replicated perfectly. However, that doesn’t prove the method correct. And that is the point, We want to know something about the real world and it’s history – all of these proxies and methods are just means to an end. It is far more important to see whether there is a consistency between corals and deep sea sediment and ice cores and models than it is to validate someones spread sheet. Sure sometimes people make mistakes in analyses, sometimes methods are inappropriately used. But this stuff comes out in the wash usually because of comparisons with other ways of getting to the same thing, not because half the population of scientists are engaged in checking what the other half did. – gavin]

Gavin, you say the debate is about the role of CO2 as a GHG. I don’t see that as debatable, everyone knows that CO2 is a greenhouse gas. I also don’t see that man has been increasing CO2 is subject to debate either. The real debate is about the magnitude of the effect incremental CO2 has on the climate.

This article is about tree ring data as temperature proxies and whether or not those on either or both sides cherry picked data to support a particular position. My point is that it really doesn’t matter since tree ring data is affected by many things and can be considered reasonable temperature proxies only when everything else that affects tree growth is held constant. To me, your mention of Arrhenius referred to the equation named for him that quantifies the rate of chemical reactions as a function of temperature, not that Arrhenius considered CO2 a GHG, for I don’t consider that to be wrong. Excuse me for assuming you were using a scientific principle to justify your argument. I should have known better, assumptions are generally incorrect.

I just love the use of the word “deniers” to describe those of us who are not yet convinced that the climate data we have supports the claims much less the conclusions of the IPCC. I really wonder why people have such a hard time keeping an open mind. I am open to the possibility that there is a warming trend being caused by man, but nothing about the data is conclusive. And just because people are willing to say it is conclusive does not make that statement so.

>Absolutely. Publish all the data, publish all the code. Then watch them hang themselves with it

Exactly. Giss published, and it is not attacked as much. If Briffa had published everything sooner, this would have been cleared up. Isn’t the point to have your work stand up to scrutiny? Let everyone see it and try to find something wrong with it.

The paper you cited isn’t available, except via PPV or subscription access. The abstract says that the influence of elevated CO2 is less than expected, but it doesn’t say what was expected and it certainly doesn’t say that it was zero.

The hockey stick of CO2 is what we want to know the effects of, surely, rather than evidence of warming? There’s a pretty good hockeystick in sunspots, which all qualified comment seems to conclude is pretty much irrelevant. Just a thought.

What conclusion do you make? -CO2 being a greenhouse gas explains why tree ring width only responds to a change in temperature?

This snippet … posted in ignorance … actually gives the lie to what McI et al are claiming.

No, Briffa and other scientists don’t state that tree ring width only responds to a change in temperature. Quite the obvious.

Thus the need to *carefully* select data from trees where there’s solid evidence that THOSE PARTICULAR TREES are responding primarily to temperature. For instance, in Briffa et a 2001 they talk about trees being near altitudinal or longitudinal limits being good candidates because range is limited by temperature (not CO2 concentrations, or precip) and therefore relatively minor changes in temperature cause a relatively larger change in growth rate than trees growing in an area where conditions are more optimum.

It’s McI (to some extent) and the chorus (to an overwhelming extent) saying “ALL THE TREE DATA MUST BE USED! ANY SELECTION CRITERIA IS CHERRY-PICKING!”. And McI sweetens the deal by insisting that those chosen by Briffa’s methodolgy be ignored.

Sweet irony.

So, to repeat:

What conclusion do you make? -CO2 being a greenhouse gas explains why tree ring width only responds to a change in temperature?

I would now hope that Rob will go to WUWT and CA and explain to people that trying to use tree ring data without any kind of selection methodology to weed out those which don’t appear to be mostly responding to temperature changes is wrong, wrong, wrong.

“I can provide photos of each hair, spreadsheets of the count and exact locations that can be verified by anyone and replicated perfectly. However, that doesn’t prove the method correct.”

I think that you are a little confused in your concept of the scientific method, Gavin. The objective of replication is not to prove something correct. Rather it is that a failure of replication proves it to be incorrect – assuming that the correct proceedure was followed. If you are a good scientist you want to know if there could be a failure to replicate. To that end you want as many people to try to replicate as you can get. When you hide any of the means of replication it indicates that you don’t want the attempt to be made because you fear failure. You also make the faulty argument about your own methods and then transfer that to saying that all climate scientists are trying to be transparent. I shouldn’t have to explain why that argument doesn’t work.

[Response: Don’t be so obtuse. The general point is perhaps something we can agree on – replication does not imply correctness. Far more important given the fact that we are dealing with climate proxies in this instance is whether we are interpreting them correctly. And much more progress is being made by looking at that, than is being made checking anyone’s arithmetic. – gavin]

> but I am troubled – I am a layman. I regularly debate
> issues with skeptics and rely on comments from the folks
> here to defend my position …. I simply do not see why
> any data or methodology should be withheld from wider
> scrutiny unless you have something to hide ….

Sounds like you haven’t learned the science or the facts yourself, and this means you’re playing their game, on their terms, in their context. You may do better by not trying to debate by copypasting science, but instead learning how to look up the information and helping people get past the notion that “debate” is useful in educating people about science. It generally fails.

And it sounds like they’ve suckered you into believing their nonsense about this issue. I’d be troubled too.
Concerned, even.

Just got to get another two cents in regarding all this stuff about openness and transparency.

First off, I think it’s a good idea. For my part, most of the funding for the work I do normally comes with the condition that the data be made publicly available at the end of the project and I, for one, don’t have any problems doing that. However, there are many reasons for withholding data, at least in the short term, so people shouldn’t be so quick to accuse Briffa of being sneaky.

One specific issue which I don’t think has been mentioned yet is the replication of the result using completely different data and/or methods. With any good experiment, it should be possible to replicate the conclusion without the original data and in some ways, it is desirable to not cross-pollinate data too much in order to preserve independence. I’m not saying that data should be withheld permanently, but competing groups finding the same answers without each other’s help (as has demonstrably happened here) definitely benefits the overall science in the long run.